Estimation of the amount of refrigerant in artificial ground freezing for subsea tunnel

해저터널 인공 동결공법에서의 냉매 사용량 산정

  • Received : 2018.01.02
  • Accepted : 2018.02.26
  • Published : 2018.03.31


Subsea tunnel can be highly vulnerable to seawater intrusion due to unexpected high-water pressure during construction. An artificial ground freezing (AGF) will be a promising alternative to conventional reinforcement or water-tightening technology under high-water pressure conditions. In this study, the freezing energy and required time was calculated by the theoretical model of the heat flow to estimate the total amount of refrigerant required for the artificial ground freezing. A lab-scale freezing chamber was devised to investigate changes in the thermal and mechanical properties of sandy soil corresponding to the variation of the salinity and water pressure. The freezing time was measured with different conditions during the chamber freezing tests. Its validity was evaluated by comparing the results between the freezing chamber experiment and the numerical analysis. In particular, the freezing time showed no significant difference between the theoretical model and the numerical analysis. The amount of refrigerant for artificial ground freezing was estimated from the numerical analysis and the freezing efficiency obtained from the chamber test. In addition, the energy ratio for maintaining frozen status was calculated by the proposed formula. It is believed that the energy ratio for freezing will depend on the depth of rock cover in the subsea tunnels and the water temperature on the sea floor.


Grant : 고수압 초장대 해저터널 기술자립을 위한 핵심요소 기술개발

Supported by : 국토교통과학기술진흥원


  1. Andersland, O. B., Ladanyi, B. (2004), Frozen Ground Engineering (Second edition). Chichester: John Wiley & Sons, Hoboken, New Jersey, pp. 363.
  2. Colombo, G., Lunardi, P., Cavagna, B., Cassani, G., Manassero, V. (2008), "The artificial ground freezing technique application for the Naples underground", Proceedings of the World Tunnel Congress 2008 on Underground Facilities for Better Environment and Safety, Agra, India, pp. 910-921.
  3. Handbook of Chemistry and Physics (84th Ed, 2004), Boca Raton, FL : CRC-Press/Taylor and Francis.
  4. Hass, H., Schafers, P. (2005), "Application of ground freezing for underground construction in soft ground", Proceedings of the 5th International Symposium TC28, Amsterdam, The Netherlands, pp. 405-412.
  5. Heijboer, J., Hoonaard, J., Linde, F.W.J. (2004), The Westerschelde tunnel: approaching limits, A.A. Balkema, The Netherlands, pp. 292
  6. Itoh, J., Lee, Y. S., Yoo, S. W., Lee. S. D. (2005), "Ground freezing improvement for TBM maintenance in Singapore", Proceedings of the International World Tunnel Congress and the 31st ITA General Assembly, Istanbul, Turkey, pp. 471-476.
  7. Pimentel, E., Papakonstantinou, S., Anagnostou, G. (2011), "Case studies of artificial ground freezing simulations for urban tunnels", Proceedings of the Word Tunnel Congress 2011 on Underground Spaces in the Service of a Sustainable Society, Helsinki, Finland, pp. 459-468.
  8. Pimentel, E., Papakonstantinou, S., Anagnostou, G. (2012), "Numerical interpretation of temperature distributions from three ground freezing applications in urban tunneling", Tunnelling and Underground Space Technology, Vol. 28, No. 1, pp. 57-69.
  9. Sanger, F. J., Sayles, F. H. (1979), "Thermal and rheological computations for artificially frozen ground construction", Engineering Geology, Vol. 13, No. 1-4, pp. 311-337
  10. Stoss, K., Valk, J. (1979), "Uses and limitations of ground freezing with liquid nitrogen", Engineering Geology, Vol. 13, No. 1-4, pp. 485-494.
  11. Son, Y.J., Lee, K.W., Ko, T.Y. (2014), "Studies of application of artificial ground freezing for a subsea tunnel under high water pressure - focused on case histories", Journal of Korean Tunnelling and Underground Space Association, Vol. 16, No. 5, pp. 431-443.